JP2830346B2 - Optical disk protection device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an optical disk protection device used for an optical disk recording / reproducing device.

2. Description of the Related Art In recent years, an optical information recording / reproducing apparatus that records an information signal on a disk using a laser beam or reproduces an information signal from the disk has been developed.

In this information recording / reproducing apparatus, focus control is performed to accurately irradiate the recording surface of the disk with light from an optical pickup. If the focus control is out of focus due to external vibration, control malfunction, or the like, the objective lens collides with the disk, and the objective lens and the disk remain damaged. In the optical disk device, such damage must be avoided because it causes a malfunction of the device.

Hereinafter, an example of a conventional optical disk protection device will be described with reference to the drawings.

FIG. 2 shows a conventional optical disk protection device. In FIG. 2, 3 is an optical pickup, 4 is an objective lens, and 7 is a guide rail for moving the optical pickup. Reference numeral 6 denotes a rotation fulcrum of the guide rail 7, and the guide rail swings about the fulcrum 6 in a direction perpendicular to the disk surface. 8 differential amplifiers, 9 phase compensation circuits, 10
The focus control is performed by the switch 11 and the drive amplifier 11. Reference numeral 12 denotes a disk warpage detection circuit, and a drive amplifier 13 drives 15 motors. 14 is a focus abnormality detection circuit, and 16 is a logical sum.

The operation of the optical disk protection device configured as described above will be described below.

First, when the focus control is operating, switch 10
It is ON. Next, if the focus deviates for some reason, the focus abnormality detection circuit 14 operates and the logical sum 16
By turning off the switch 10 and stopping the focus control operation, the objective lens 4 is moved away from the disk 1 to avoid collision between the disk 1 and the objective lens 4 (for example, application number 2-13163). .

Further, the focus abnormality detection circuit 14 uses the following method in many cases.

Light emitted from the objective lens 4 is reflected by the disk 1 and is emitted to the optical sensor. As the optical sensor, those divided into four as shown in FIG. 3 are often used, and 17a, 17b, 17c,
The sum Ps of all outputs of 17d changes with the distance between the objective lens 4 and the disk 1, as shown in FIG. The output sum is input to a comparator to detect whether the objective lens 4 and the disk 1 are too close or too far.

SUMMARY OF THE INVENTION However, in the above-described configuration, even if a focus error is detected and focus control is stopped, the pickup is set so that the optical axis of the light beam is always substantially perpendicular to the warpage of the disk 1. In order to incline 3, depending on the shape and size of the warpage of the disk, the objective lens 4 may approach the disk 1 instead of stopping the focus control,
There is a problem that the objective lens 4 may collide with the disk 1.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides an optical disk protection device that can eliminate damage caused by collision between a disk and an objective lens with a simple configuration.

Means for Solving the Problems In order to solve the above problems, an optical disk protection device according to the present invention is provided with a detection circuit for detecting a focus error, a switch for stopping focus control, a motor for moving a guide rail, and detection of a focus error. Means for stopping the focus control and moving the motor to move the guide rail away from the disc, and before the focus control means starts operating, driving the means for inclining the optical pickup to a position farthest from the optical disc in advance. The optical pickup is configured to be tilted.

Effect of the Invention According to the above-described configuration, when the focus is pulled in, the distance between the objective lens and the disc is set farthest in advance, and when a focus abnormality is detected, the focus control is stopped and the guide rail is driven. By increasing the distance between the lens and the disk, it is possible to eliminate damage resulting from the collision between the objective lens and the disk.

Embodiment An optical disk protection device according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a first embodiment of the present invention. The disk 1 is driven to rotate by a disk motor 2. A pickup 3 including an objective lens 4 and a linear motor 5 for generating a thrust thereof are both mounted on a guide rail that can swing up and down around a rotation fulcrum 6, and the disk 1
Move in the radial direction. The output of the detector for detecting the inclination in the pickup 3 is applied to the drive amplifier 13 through the disk warpage detection circuit 12, and the output of the drive amplifier is rotated by the motor 15 so that the light beam emitted from the objective lens 4 A control loop is configured to control the guide rail 7 in the vertical direction so that the irradiation surface of the disk 1 is always perpendicular. The output of the focus signal detecting optical sensor in the pickup 3 is turned on / off by a switch 10 via a differential amplifier 8 and a phase compensation circuit 9, applied to a drive amplifier 11, and drives the objective lens 4 to perform focus control. It is carried out. Further, the output of the focus signal detection optical sensor in the pickup is applied to the focus abnormality detection circuit 14.
When the focus error detection circuit 14 detects a focus error, it sends a signal to the logical sum 16 and the drive amplifier 13 to switch
Turn off 10 to stop focus control and motor 15
Is driven to move the guide rail 7 away from the disk 1, thereby moving the objective lens 4 on the pickup away from the disk 1.

As described above, according to the present embodiment, when a focus error occurs, the focus control is stopped and the objective lens 4 is stopped.
By moving the guide rail 7 in a direction away from the disk 1, damage to the disk 1 and the objective lens 4 due to collision between the disk 1 and the objective lens 4 can be eliminated.

Hereinafter, a second embodiment of the present invention will be described with reference to the drawings. FIG. 5 shows a second embodiment of the present invention. In the figure, the configuration is the same as that of FIG. 1 except that a focus loop ON / OFF signal is applied to the drive amplifier 13. In the optical disk protection device configured as described above, the guide rail 7 is provided both when the focus control is stopped and when a focus error occurs.
Is in a direction away from the disk 1, and when the focus control is started, the disk 1 and the objective lens 4 are away from each other. Thus, it is possible to eliminate damage to the disc 1 and the objective lens 4 due to the collision between the disc 1 and the objective lens 4 at the time of focusing.

Effect of the Invention As described above, according to the present invention, a collision between a disk and an objective lens can be eliminated with a very simple circuit configuration, and it is extremely effective practically as a device for protecting an optical disk.

[Brief description of the drawings]

1 is a block diagram of an optical disk protection device according to a first embodiment of the present invention, FIG. 2 is a block diagram of a conventional optical disk protection device, FIG. 3 is a plan view showing an example of an optical sensor, and FIG. Is a diagram showing the output of the optical sensor with respect to the distance between the objective lens and the disk, and FIG. 5 is a block diagram of the optical disk protection device according to the second embodiment of the present invention. 1 disk 2 disk motor 3 pickup 4 objective lens 5 linear motor 6
... Rotating fulcrum, 7 ... Guide rail, 8 ... Differential amplifier,
9: phase compensation circuit, 10: switch, 11: drive amplifier, 12: disk warpage detection circuit, 13: drive amplifier,
14 Focus anomaly detection circuit, 15 Motor, 16
OR.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G11B 7/08-7/095

Claims (1)

(57) [Claims] 1. An optical pickup for irradiating an optical disk, which is a disc-shaped recording medium, with a light beam to record or reproduce an information signal such as a video signal, and wherein the optical axis of the light beam emitted from the optical pickup is set on the optical disk. Means for tilting the optical pickup with respect to the warp of the optical disk so as to be substantially perpendicular to the signal recording surface, and a light beam spot irradiated from an objective lens in the optical pickup is focused on the signal recording surface of the optical disk. A focus control means for driving and controlling the objective lens, and an abnormality detection means for detecting an abnormal operation of the focus control means, wherein the focus control is performed when the abnormality detection means detects an abnormal operation of the focus control means. Means for stopping the operation of the means and for tilting the optical pickup away from the optical disk An optical disk protection device for tilting the optical pickup, the drive control of the tilting means of the optical pickup in response to a stop command of the focus control means, and the drive control of the objective lens such that the light beam spot is focused on the signal recording surface of the optical disk. Before the focus control means starts operating, the means for tilting the optical pickup is driven,
An optical disk protection device for protecting an optical disk by previously tilting an optical pickup to a position farthest from the optical disk.